Coexistence of prompt and delayed decay modes of energized polyatomic molecules is discussed with reference to the special features of larger molecules which makes it amenable to experimental observation by a suitable choice of initial conditions. The molecular parameters identified by the RRKM theory of unimolecular (delayed) decay suffice to characterize the prompt process as well. The expected "kinetic stability" of large molecules is thus not necessarily the rule, and fast processes are possible, suggesting the possibility of experimental control.